Dust gauge



Aug; 27, 1946.

DUST GAUGE Filed June 19, 1943 INVENTOR.

\ H. w. SHERIDAN" 2,406,409

Patented Aug. 27, 1946 UNITED. STATESPATENT FFICE DUST GAUGE Hiram W. Sheridan, Oak Park, 111. Application June 19, 1943, Serial No. 491,482

3 Claims.

This invention relates and the like.

One of the objects of the invention is the provision of new and improved mechanism for determining the relative amount of dust particles, or other foreign matter, floating in'the atmosphere.

A further object of the invention is the provision of new and improved mechanism for continuously indicating the presence of dust particles, or other foreign matter, in still air or air flowing through a, predetermined passage, however the current may have been induced.

A further object of the invention is the provision of a new and improved apparatus for indicating the relative amount of foreign particles floating in an atmosphere of gas of any type whatever in which such information is desired.

Other and further objects and advantages of the invention will appear from the following description, taken in connection with the accompanying drawing in which Fig. 1 is a perspective view of the apparatus,

to dust testing devices,

with parts broken away, showing the invention more or less diagrammatically; and

Fig. 2 is a diagrammatic illustration of the in.- vention.

In numerous industries a great amount of dust is generated incident to the manufacture of certain products, and in the manufacture of certain material this dust is impalpably fine and of such a nature that a certain percentage in the air renders the mixture more or less explosive, and great damage has been done by the explosions of such mixtures.

In certain other industries the dust created or generated incident to the manufacturing operation is seriously injurious to the health of the operators of the various machines in the plant. In certain other industries the amount of dust in the air is a material consideration in all installations for filtering the air.

In still other industries the nature of the products necessitates the use of air that does not contain a percentage of foreign matter above a predetermined minimum.

In any of these industries, as well as in many others, such as air conditioning for dwellings, oflices, and the like, it is desirable to determine the percentage of dust, or other foreign particles, in the air within the plant and introduced in the buildings, in order to properly regulate the air cleaning and filtering apparatuses employed. The conventional apparatus usually employed for this purpose is complicated and more or less expensive.

The present invention seeks to overcome these objectionable features by the provision of a simenced, at-little timeand expense.

may be provided with a handle Referring now to the drawing, the reference character I0 designates a box or cabinet which comprises a top wall I walls l3, l4, and end walls I, a bottom Wall l2, side l5, I6. The cabinet I! on its upper wall for carrying the device. A sinuous passage l8, having at least one straight portion I9, is mounted within the cabinet to. This passage may be provided in any suitable manner, but is preferably of uniform cross-section throughout its length. The upper end 2| extends to the sur face of the endwall I6, and is preferably flush 'therewith. The lower end of the passage I 8 also extends through the end wall l6, and a blower or exhaust fan 22 is mounted over the lower end of this passage, so that when the fan is in operaand pass through and be discharged Mounted on the end .wall I6 of the chamber is a casing 24 in which is mounted a source of light, as the lamp bulb 25, for illuminating the straight portion IQ of the passage l8, the lamp being controlled by a switch 20. The axis of the bulb 25 is in alignment with the tion [9 of the passage, and is also opposite an opening 26 in said end wall. Mounted in the opening is a pair of planoconvex lenses 2! for collimating the rays of light passing therethrough from the bulb 25;

The sinuous passage I8 may be of any suitable material, such as Bakelite or a composition of cellulose acetate, or other artificial resin composition; or it may be of metal, if desired. The inner surface of the passage is solid black so as to absorb any light rays entering through the opening 2|. The object in making the passage sinuous is to insure that no light rays shall enter the portion sinuositites is immaterial so long as means are provided for preventing any external rays from entering the straight portion [9.

Suitable means are provided for measuring the intensity of the light rays from the bulb 25 that axis of-the straight por- I 9 of the passage. The number of 

